A soilless culture technology is an important vegetable production technology. At present, in the field of soilless culture, multiple cultivation troughs are usually placed on a supporting rack in layers, and the multiple-layer cultivation troughs are interconnected by using pipeline, so that nutrient solution flows successively from a cultivation trough at the top to a cultivation trough at the lowest layer. An existing cultivation trough is a simple rectangular trough. When the nutrient solution flows inside the cultivation trough, there are flow blind angles for the nutrient solution near the edges and corners of the cultivation trough, causing non-uniform distribution of nutrient ingredients, and affecting growth of vegetables. In addition, cultivation in layers causes a problem of shading, that is, an upper layer cultivation trough shades a lower layer cultivation trough, leading to lack of light for the lower layer cultivation trough. Pipeline connecting portions between layers of cultivation troughs and between the cultivation trough and a pump are connected by using pipe joints. When this connection manner is used, disassembly and assembly are cumbersome, and a problem of leaking is easy to occur after multiple times of disassembly and assembly.
In addition, a refrigerator is usually used to preserve vegetables at present. This preservation manner is used to preserve picked vegetables, and there is a problem that a preservation time is short.